Japanese Knotweed (Polygonum cuspidatum)
Cut japanese knotweed Three times a growing season at knee height for carbohydrate startvation.
This forces the plant to use up energy stored in roots without allowing it to regain energy from photosynthesis. The Knotweed eventually becomes small and more manageable after several years, allowing other plants to grow in that space.
regrowth of a stressed plant.
Knotweed leaves behind "standing dead" stems to save their space for the next season.
Before and After
Before and after of a mature knotweed stand behind my parents house. Repetitive cutting three times a Summer for three years significantly increased the amount of native plants able to grow in that space (naturally occurring).
Different species of Knotweed (all invasive):
Dwarf Japanese Knotweed (Polygonum cuspidatum var. compacta)
Leaves are rounder and full grown plant is more compact than it's larger relative. This form is also invasive and should be treated in the same way.